NSF/FDA SiR: Pulse Oximetry Measurement Errors Correlated with Patient Skin Pigmentation: Optical Mechanisms and Effect Multipliers

脉搏血氧计是一种功能强大、价格低廉的设备，通常用于早期发现健康问题和监测治疗。然而，研究表明，患者皮肤的色素沉着程度会影响测量的准确性。更好地了解底层机制将有助于改进工具和算法，以提高设备性能。计算模型将被用来模拟光在成人手指组织中的传播，并调查不同的生物和设备设计因素对设备性能的影响。将进行组织模拟模型的实验室测量，以在受控良好的条件下验证计算模型。这种对设备性能的有效、负担最小的评估有可能导致临床性能的改善，这将影响正在接受手术程序、麻醉和其他危重情况的患者。此外，计划中的研究将与教育、指导和推广活动无缝结合，以推进生物医学光学和监管科学领域的跨学科计划。本项目旨在开发和验证一系列脉搏血氧饱和度测试方法。这项工作的组成部分包括：(1)制作具有成人手指生物相关特性的物理模型(例如，具有不同色素水平的表皮层、仿生微血管网络和模拟心血管血流循环，以产生实时的生理流量/压力波形)；(2)建立不同大小的成人手指的电子模型，并进行蒙特卡罗模拟，以阐明脉搏血氧仪中的光-组织相互作用；以及(3)在模拟手指的物理模型中使用光谱测量来验证计算模型，并调查表皮黑色素含量以及其他生物因素(例如，灌流水平、手指大小)和设备特性(例如，光源带宽、传感器反射率)对关键光-组织相互作用参数以及对估计的血氧饱和度测量精度的影响。该项目将为影响脉搏血氧仪定量准确性的因素提供广泛的见解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Pulse oximeters are powerful and inexpensive devices commonly used for early detection of health problems and monitoring of treatment. However, studies have shown that patient skin pigmentation levels can affect the measurement accuracy. A better understanding of the underlying mechanisms will help the refinement of instrumentation and algorithms to improve the device performance. Computational modeling will be used to simulate light propagation in adult finger tissue and investigate the impact of different biological and device design factors on device performance. Laboratory measurements of tissue-mimicking models will be performed to validate the computational model under well-controlled conditions. Such effective, least-burdensome evaluation of device performance has the potential to lead to improvements in clinical performance that will impact patients undergoing surgical procedures, anesthesia, and other critical conditions. Furthermore, the planned research will be seamlessly integrated with educational, mentoring, and outreach activities to advance the cross-disciplinary program in the field of Biomedical Optics and Regulatory Sciences. This project aims to develop and validate a series of test methods for pulse oximetry. The components of this work include: (1) Fabricating physical models with biologically relevant properties of adult fingers (e.g., epidermal layers with different pigmentation levels, bio-mimetic microvascular networks, and mock cardiovascular flow loop with tunable oxygenation to generate real-time physiological flow/pressure waveforms); (2) Developing in silico models of adult fingers of different sizes and performing Monte Carlo simulations to elucidate light-tissue interactions in pulse oximetry; and (3) Validating computational models using spectroscopic measurements in finger-simulating physical models, and investigating effects of epidermal melanin content along with other biological factors (e.g., perfusion level, finger size) and device characteristics (e.g., source bandwidth, sensor reflectivity) on key light-tissue interaction parameters, as well as on estimated oxygen saturation measurement accuracy. This project will provide extensive insights into the factors influencing quantitative accuracy of pulse oximetry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.